1. Field of the Invention
The present invention relates to a seat used in automobile, and in particular relates to an automotive seat having a main foam cushion body and secondary cushion body of a softer foam material with respect to the main cushion body for the purpose of improving a seating comfortableness of the seat.
2. Description of Prior Art
In order to improve a seating sense of an automotive seat, there is provided a multiple layer seat which includes a main cushion body and secondary cushion body mounted on the main cushion body.
Reference is made to FIGS. 1 and 2, in which this kind of conventional seat (in this embodiment, a seat cushion (A)) is shown as comprising a main cushion body (a) supported by a frame (4) and a spring member (4), and a secondary cushion body (b) fixed on the main cushion (a). The main cushion body (a) includes a main pad (8a) which is foamed in a mold, using an urethane material, and a covering member (8b) which covers the main pad (a). The secondary cushion body (b) includes a subpad (9a) made of a softer foam material (a slab, for example) than that of the main pad (a), and a covering member (7a) which covers the secondary cushion body (b).
On the surface of the secondary cushion body (b), is formed a decorative button (6a) whose dependent leg portion is fixed to the surface of the main cushion body (a). Thus, the secondary cushion body (b) is secured to the main cushion body (a) in an integral manner, by virtue of the decorative button (6a).
It is observed that a recess (c) is defined along the boundary between the main and secondary cushion body (a)(b), which adds to the aesthetic effect on the outer appearance of the seat.
Similarly, the seat back (B) comprises a main cushion body (a') and a secondary cushion body (b') with a recess (c') defined at the boundary therebetween in the same manner as the seat cushion (A).
According to thus-constructed seat cushion and back (A)(B), decorative creases are created radially at each of the decorative buttons (6a) so as to provide a plurality of decorative creases on the seating surface in a highly aesthetic fashion, because of the fact that the surfaces of the secondary cushion bodies (a)(a') are pulled down at the buttons (6a) to create the decorative creases around the buttons (6a).
However, no such decorative creases are produced in the lateral walls of the secondary cushion bodies (a)(a') by the reason of the covering members (7a, 7a') being merely stretched due to the resiliency of the sub-pad (9a), with no crease therein.
To solve this problem, there has been the proposal that the covering member (7a) of the secondary cushion body (b) is sewn with gathers to the main cushion body (a) to thereby produce a plurality of decorative creases on the lateral walls of the secondary cushion body (b). But, such decorative creases creation by gathering method requires a great number of cloth materials and assembling steps, and it is disadvantageous for enconomical and rapid manufacture of the seat.